Streamwatch Project
West Branch of White Clay Creek: Site 17
Site 17 is the only other site on the West Branch besides Site 19 and is located at Hess Mill Road upstream of Route 841. Similar to Site 19, pasture/hay fields and cultivated crops are the dominant land use in the watershed. The number of people in the watershed is typical compared to other sites, but with most of the growth occurring more recently. Water chemistry variables were comparable to the study wide average.
Macroinvertebrate densities at Site 17 were particularly low in 1991-1994 and 2003 (<3000 individuals/m2), and highest in 1995 and 1997 (<16,000 individuals/m2). Total density averaged 8300 individuals/m2 and EPT density averaged 890 individuals/m2. EPT made ≈15% of the total numbers, much lower than the reference Site 11 (56%). Total Richness and EPT Richness averaged 11 and 5 taxa/200 individuals, respectively. MAIS scores ranged from 4.5 (Poor) to 11.6 (Fair) and averaged 6.6 (Fair). The long-term trend for this site was very similar to the upstream location, Site 19, with low MAIS scores in 1996, 1997, 2004, and 2005 and high scores in 1998, 1999 and 2003. In summary there was no predictable pattern indicating whether conditions are improving or degrading for locations on the West Branch.
| Location | |
|---|---|
| Site number | 17 |
| Description | At Hess Mill Road upstream of Route 841 |
| Lat Long (hr min sec) | 39°46.091’ N, -75°49.932’ W |
| Land Use | |
| Watershed area above site (km2) | 15 |
| Population density in 2000 (#/km2) | 132 |
| % Population increase from 1990 to 2000 | 50 |
| Percent pasture/hay | 53 |
| Percent cultivated crops | 24 |
| Percent forest | 19 |
| Chemistry* | |
| Nitrate (mg/L) | 4.93 |
| Ammonium (mg/L) | 0.01 |
| Total Dissolved Phosphorus (mg/L) | 0.019 |
| Soluble Reactive Phosphorus (mg/L) | 0.036 |
| Sulfate (mg/L) | 19.07 |
| Alkalinity (as mg/L CaCO3) | 28.35 |
| pH | 7.68 |
| Conductivity (μmhos) | 192 |
| Dissolved organic carbon (mg/L) | 2.11 |
| Macroinvertebrate Data | |
| years sampled | 1991-1999, 2003-2005 |
| MAIS score | 6.6 |
| water quality based on MAIS score | Fair |
 Click on macroinvertebrate name to view a photo | |
| 1st most abundant macroinvertebrate | Chironomidae (midges) |
| 2nd most abundant macroinvertebrate | Hydropsychidae (common netspinner caddisflies) |
| 3rd most abundant macroinvertebrate | Tipulidae (crane flies) |
| 4th most abundant macroinvertebrate | Ephemerellidae (spiny crawler mayflies) |
| 5th most abundant macroinvertebrate | Oligochaeta (aquatic worms) |
*See Methods for number of years each chemistry variable was measured.